Re: Understanding EXPLAIN ANALYZE output

From: Alvaro Herrera <alvherre(at)dcc(dot)uchile(dot)cl>
To: "Ed L(dot)" <pgsql(at)bluepolka(dot)net>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Understanding EXPLAIN ANALYZE output
Date: 2005-02-09 19:04:30
Message-ID: 20050209190430.GB13746@dcc.uchile.cl
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On Wed, Feb 09, 2005 at 11:00:00AM -0700, Ed L. wrote:

> 34 -> Index Scan using idx_queryoutcome_occurrencehistory_key on queryoutcome (cost=0.00..10.28 rows=28 width=1065) (actual time=4.63..4.63 rows=0 loops=1014)
^^^^^^^^^^ ^^^^
> 35 Index Cond: ("outer"."key" = queryoutcome.occurrencehistory_key)

> If I understand these correctly, line 22's nested loop finished
> returning the last row 72.80ms into the query, and then line
> 21's nested loop returns its 0 rows 4769.59ms into the query.
> That would seem to mean 4696.79ms were spent executing the
> nested loop on line 21 prior to returning the first row.

4796.0 ms are the time it took for 34's index scan to complete the 1014
loops, I'd think.

--
Alvaro Herrera (<alvherre[(at)]dcc(dot)uchile(dot)cl>)
"La naturaleza, tan frágil, tan expuesta a la muerte... y tan viva"

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